592 GREAT SERPENTINE BELT OF NEW SOUTH WALES, ii., 



the eruption of the older basalts, and which was repeated on a 

 grander scale, before the Newer Basaltic Period. (Fig. 6). 



-4oooe7 **yt Ef>hraim 



4 Milts 



Fig. 6. 



The manner of eruption of the basalt is unexpected, while, in 

 general, the mode of occurrence is that of plateau-basalts derived 

 from fissure-eruptions, as stated by Mr. Harker(33). No fissures 

 (dykes) can be found, except a small one in a fault-plane crossing 

 Jimmie's Creek, and one, 10 yards wide, intruding the dolerite 

 north of Ruzicka's Hill. On the other hand, at least six basalt- 

 necks have been found as follows (Fig. 3) : — 



(1) Donald's Mount at Nundle, a hill chiefly of basalt intruding 

 into the slates (about 120 x 170 yards in area). 



(2)Nuggety Sugar loaf, south of Nuggety Creek, a steep hill 500 

 feet high, the southern side of which is basalt, about 500 x 400 

 yards in area. 



(3) A circular patch of basalt, about 30 yards in diameter, on 

 the ridge east of Munro's Creek. 



(4), (5), and (6). The patches of basalt in the valley of Munro's 

 Creek, near the Razorback, respectively 160 x 120, 50 x 50, and 

 20 x 20 yards in approximate area. The last is strongly prismatic, 

 and makes a small hillock overlooking the tributary creek at this 

 point. 



